Hypodermic syringe.



PATENTED JULY 81, 1906 HYPUDERMIU SYRI APPLICATION FILED JUNE 27, 1904W. KORE.

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FREDERICK WM.

KORB, or CLEV ELAND, OHlO, ASSIGNOR TO THE UNITED STATES DENTALMANUFACTURING COMPANY, OF CLEVE- LAND, OHIO, A CORPORATION OF OHlO.

uveoosnmio SYHENGE.

Specification of Letters Patent.

Patented July 31, 1906.

Application filed June 27,190i. Serial No. 214,276.

To all whom it Til/(L1; concern:

Be it known that l, FREDERICK War, Konn,

a citizen of the United States, residing at skilled. in the art to whichmy invention pertains to make and use the same, reference being had tothe accompanying drawing, which forms a part thereof.

My invention relates to hypodermic syringes adapted to be operated bydirect pressure between the palm and fingers of the operator. itsobjects are to produce a syringe in which very great pressure may becreated on the liquid to be ejected from its barrel and to guide andprotect the very small or slender piston-plunger against being sprung orbent in operation; and it consists of certain features and combinationsof features, as will hereinafter be specifically set forth and Thedrawing shows a central longitudinal section of my invention in thegeneral form and construction of details now deemed most desirable byme; but changes not requiring the exercise of invention might be madetherein by a shilful mechanic without departing from the spirit of myinvention as set forth in the claims at the end of this specification.

My invention contemplates form of syringe in which very great pressuremay be produced on the liouid in the barrel by the direct grippingpressure of the operators hand and without the intervention ofpowerlevcrs, screws, or other such mechanisms intended to multiply thegripping pressure of the operate-Es hand.

Powensyringes are particularly desirable where cocaine or otherobtundant or anesthetic liquids are to be forced into bones or into thedentin structures of teeth to deaden or stu ely the nerve centers. Insuch operations very minute portions only of the liquids say a drop ortwoare absorbed by the bone or dentin structures into which they areforced, and such quantity as is used is only a very small percentage ofthe capacity of an ordinary-sized hypodernnc syringe, the barrels and pstons of which are usually about livc-sixtcenths of an inch in diameter.This diameter, iive-sixteenths of an inch, has an area of aboutone-thirteenth of a square inch, and ifthe grip of the operators handequals fifty pounds it would produce a ressure on the liquid of about.six hundred and fifty pounds per square inch. N ow if power mechanismis employed to aid the operator with a ratio or leverage of, say, fourto one it would raise the pressure on the liquid to two thousand sixhundred pounds per square inch.

With my invention 1 purpose producing very much greater pressures thanthis by the use of a syringe barrel and piston of very small diameterand reduced area. In prac: tice I have found that a barrel and piston ofone-eighth inch diameter and one and onehalf inches stroke willdischarge a many times greater quantity of the liquid than will beabsorbed by the part into which. it is forced, so that a syringe of thissize has ample capacity for such operations. Now a piston-plunger ofone-eighth inch diameter has an area of about 1/ of a square inch, andif theopcrators grip equals fifty pounds, as before, it would produce apiston-pressure on the liquid of four thousand and seventy-five poundsper s uare inch A piston-pluiiger of such small diameter as one-eighthof'an inch or less is not, however, sufliciently rigid if unsupported orunguided where it projects from the back end of the barrel to insure itagainst being sprung and bent in the strong grasp of the operatpr, andit is the purpose of m in vention to produce a structure that wil se-.

curely guard against such accidental bending of the piston and limit themovement of the pis ton and prevent its being accidentally pul edentirely out of the barrel. 4 g

r In the drawing I showon an enlarged scale a central longitudinalsection of a syringe embodying my improvements.

The barrel A has a small longitudinal bore.

a, in which is fitted a small piston-plunger B. The forward end of thebarrel'is formed with a small screwed ni ple erture a smaller than t ebore of the barrel, and on this nipple is screwed nozzle or needle point(1, having a milled ledge c, and seating against a packing-washer c ofleather or also to provide stops to 0/, having an ap.-

. end of the barrel.

other suitable material, located in an annular recess in front face ofthe shoulder a on the barrel.

The rear end of the barrel is screw-threaded to receive a cap E, boredat e for the passage of the piston-plunger and inclosing packing-washersf, which it clamps against the From the back of the cap E there is atubular extension or uidesleeve E, bored, as at e, considerably argerthan the diameter of the barrel and pistonplunger. In this sleeve liesan extension B" of the piston-rod sufficiently large in diameter toguard against any chance of its being bent or sprung when drawn out ofthe sleeve and having a collar 12, which fits the bore of the sleeve, asshown.

On the end of the sleeve is screwed a ca E bored to fit the pistonextension B, this cap and the collar serving to guide the pistonextension B throughout its stroke and also to limit the stroke of theiston.

On the projecting end 0 the piston-rod is a palm-button F, and onthe capE, at a point relatively near the rear end of the cylindrical barrel andthe mid-length of the device, is secured a cross-bar F, suitably curvedto be engaged by the fingers of the operator.

It will be observed direct action of an ordinary syringe, that its smalldelicate piston-plunger is eii'ectually ]protected and guided, thatits'movement is imited in both directions by the collar on the pistonextension, and that the structure is compact and symmetrical, everyfeature of it being in alinement on the axis of the barrel and pistonand without side projections of any kind except the finger-bar F;

Having thus described my invention, what I claim as new and useful, anddesire to se cure by Letters Patent, is-

1. In a syringe, the combination of the cylindrical barrel, apiston-plunger fitted therethat my syringe has the in and having anextension of larger diameter than the iston portion, an extension fromthe barrel of less length than the enlarged portion of thepiston-plunger and adapted to serve as a guide there or, a palm-piece onthe projecting extremity of the piston-piece and a cross-bar-secured tothe device relatively near the rear end of the cylindrical barrel.

2. In a syringe, the combination of the cylindrical barrel, apiston-plun er fitted therein and having an extension of iarger diameterthan the plunger portion with a collar at the inner end of said enlargedportion, an exten-. sion fromthe barrel of less length than the enlargedportion of the piston and adapted to serve as a guide therefor, stops insaid barrel extension adapted to act upon the collar on the pistonpiece, with a palm-piece 'on the projecting extremity of the piston-pieceand a cross-bar secured on the device relatively near the rear end ofsubstantially as described.

3. In a hypodermic syringe, the combination of the cylindrical barrel, apiston-plunger the cylindrical barrel fitted in the barrel and having anenlarged extension provided with a collar, a tubular sleeve screwed uponthe barrel with an inner wall apertured for the piston-plunger, and

forming a packing-chamber, the bore of the sleeve adapted to receive thecollar on the rod, a cap screwed upon the end of the sleeve and bored tofit the enlarged portion of the rod, with a'pahn-button on the end ofthe piston-rod and a cross finger-piece secured to the device near therear end ol" the barrel; substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

FREDERICK WM. KORB. Witnesses:

WM. A; SKINKLE, SAMUEL C. BLArrE.

